Purpose of Review Reflectance confocal microscopy (RCM) enables imaging of skin lesions at cellular level resolution at the bedside (in vivo) or in freshly excised tissue (ex vivo). This article provides an overview of strengths and limitations of non-invasive RCM in skin cancer diagnosis. Recent Findings RCM features of common melanocytic and non-melanocytic skin neoplasms such as melanoma, actinic keratosis/squamous cell carcinoma, basal cell carcinoma, and nevi have been well defined and show good correlation with dermoscopic and histopathologic findings. Due to its technical properties, RCM is especially suitable for the examination of flat skin lesions. Summary In vivo RCM has been shown to increase the accuracy of non-invasive diagnosis of common skin neoplasms and is a valuable adjunct to dermoscopy, particularly in cosmetically and functionally sensitive areas such as the face or the genital area.

Reflectance confocal microscopy (RCM) enables in vivo imaging of human skin at a quasi histologic resolution. The black-and-white RCM images show horizontal sections of the skin, at a maximum depth of 350 microm. To date, the RCM features of a significant number of skin conditions have been described. The main focus of the research community investigating RCM, however, lies on describing and diagnosing melanocytic skin lesions. Taking into account all RCM studies dealing with diagnostic accuracy in melanocytic skin lesions, sensitivity and specificity of approximately 90% and 86% could be found. Improvement of diagnostic accuracy, improved assessment of dermoscopic-histologic correlation, in vivo biopsy side selection, surgical margin assessment, and response control of conservative therapies in skin diseases are some of the major advantages of this novel imaging method. Additionally, RCM holds inherent potential for teledermatologic application and automated image analyzing. This article describes morphologic features of diverse skin lesions and features of "normal skin," summarizes diagnostic advances of RCM, compares studies dealing with diagnostic applicability, and discusses further research goals of this exciting new imaging technique.

The present study was conducted to identify possible dermoscopic patterns, associated with mitotic rate > 1/mm², histological ulceration in melanoma and metastatic disease. For this retrospective data analysis all clinical and dermoscopic digital images of primary malignant melanomas between 2008 and 2013 documented at the Department of Dermatology Graz were included, using the internal image data-base. 550 patients with 559 melanomas were included. While clinical or dermoscopic analysis considered ulceration to be present in 120 (21.5%) and 117 (20.9%) of all lesions, respectively, histopathology reported ulceration in only 96 cases (17.2%). The presence of milky-red areas, shiny-white streaks, a blue-white veil and blue-grey areas in dermoscopy is highly correlated with histological ulceration and a mitotic rate > 1/mm². The dermoscopic patterns shiny-white streaks, milky-red areas and blue-white veil were also significantly associated with development of distant metastases. Our study proves a significant correlation between the dermoscopic patterns "blue white veil“, "milky-red areas”and "shiny-white streaks”and the histological findings "ulceration”and "mitotic rate > 1/mm²“. Furthermore these dermoscopic patterns are highly related to distant metastases. Thus, dermoscopy renders earlier prognostic statements possible.